Hi Gregg,
Please deactivate the data source in ecc side at RSA5 and try to delete in bw side.
Bw Side go to RSA1, Left side click on Data source, in right side panel find 0FL_GI_10, try to delete it.
Or
While replicating data source if you migrated, again migrate back to 3.x by using RSDS and try to delete it after de-actiavted at ecc side.
Thanks